Main Sub-Main Distribution Boards Testing and Commissioning Procedure

Method Statement For The Testing and Commissioning of Main Sub-Main Distribution Boards (MSMDB) Sub-Main Distribution Boards (SMDB) Distribution Boards (DB) and Consumer Units(CU)

TESTING, COMMISSIONING AND START UP PROCEDURES

  • Upon completion of equipment installation and prior to carrying out test runs, the Contractor shall visually inspect the installation and satisfy that the equipment has been properly installed.
  • Ensure that all moving parts (if any) are free from obstructions.
  • It should be ascertained that the system has been installed in accordance with the design and installation drawings, and that each piece of equipment operates properly.
  • Manufacturer’s instructions, where applicable, will be followed for testing and commissioning of the system components.
  • All recommendations as per standards and regulatory requirements applicable to the project shall be followed.

Preparation

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Prior to system operation the Contractor together with the Engineer visually inspects and attests that the system is ready for operation. The following shall be observed:

Punch list: The contractor shall see to it that all the punch list items that may directly affect the system tests were all complied with and/ or resolved with the Engineer/ Client.

Notification: The Contractor shall notify the Engineer and/ or Client representative of the time and date when the test/ inspection shall be performed. The Contractor shall notify the Engineer and/ or Client representative 48 hours before the actual inspection to enable them to witness the tests. The values will be recorded and submitted for further approval.

Testing procedure MSMDB’s and SMDB’s

The following tests are to be carried out in a distribution board:

  • Verification of nameplate details for rating in accordance with approved General Arrangement (GA) drawings
  • Check for physical damage
  • General checksdistribution board testing procedure
  • Check for Electrical/ Functional checks
  • Insulation Resistance tests
  • Check earthing connection

Test equipment/ instruments:

  • Insulation resistance tester with variable voltage selections
  • Multi-meters

Insulation resistance test – Procedures

  • Check for the tightness of all connections
  • Clean all the supporting insulators
  • Isolate the cables on incoming and outgoing side
  • Apply a Megger voltage of 1000 Volts DC with Respective Phases for one (1) minute and record the values
  • Similarly, continue the test and record the values for the other phases

Electrical/ Functional Checks – Procedures

  • Switch on the main incoming control supply for the SMDB
  • Check the electrical operation of the switchgear using the schemes
  • Check the operation of the indicating devices, voltmeters, protective devices, etc. mounted in the panel using the scheme

Testing procedure of DB’s & CU’s

The following tests are to carried out in a distribution board:

  • Verification of nameplate details for rating in accordance with approved General Arrangement (GA) drawings
  • Check for physical damage and earthing connection
  • General checks
  • Check for Electrical/ Functional checks
  • Test equipment/ instruments:
    • Multi-meters

Electrical/ Functional Checks – Procedures

  • Switch on the main incoming control supply for the SMDB
  • Check the electrical operation of the circuit breaker
  • Check the availability of voltage on circuit breaker by using Multi-meter
  • Check the operation of the indicating devices, Voltmeters, protective devices, etc. mounted in the panel using the same scheme

Before Energisation

Check:

  • Busbar chambers, main and sub-main switch connections i.e. bolts and nuts tightness.
  • Earthing connections at compartments, all switches and earth electrodes.
  • Clearance of live parts from direct contact with or any likelihood of contact with tools, spurious bare conductors remaining in switches, circuit breakers and switch cubicles.
  • Vacuum cleaning of switches and Breakers.
  • Provision of danger and warning signs.

Switch on Process

  • Whenever there is any break of time e.g. the next day, in carrying out the switch on process, re-test of insulation resistance is required.
  • Switch on the main incoming with all other out going breakers off.
  • If normal, switch on other sub-main switches one by one with all other outgoing switches off.
  • If normal, then switch on all other out-going switches one by one.
  • Keep vigilance for about 30 minutes to see if any smell or abnormal noise is being generated.

Acceptance:

After the system is thoroughly tested and inspected and all comments have been duly complied and rectified, the Engineers shall sign the Acceptance Certificate certifying that the system is fully accepted and shall be ready for handing over to the owner.

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